Computing systems often portray a background image on their display screens. These background images are usually static to prevent them from distracting the users of the computing systems. However, if the computing system has not been used for a while, dies the static image is sometimes replaced with an active one (sometimes called a “screen saver” for historical reasons).
Whenever the computing system wishes to present to its user some visual information (e.g., a system message, application or folder icons, a status bar, or an application window), the visual information is written over, that is, it obscures an area of the background image. In some implementations, the overwriting is done semi-transparently so that the underlying image can still be made out.
A user of a personal computing device often chooses a background image that is somehow meaningful to that user. For example, the user may choose for a background an interesting geometric pattern or a photograph of, say, his family.